The lack of appropriate technology has limited the scope of research on non-MHC antigens. Using recently developed cell culture techniques and antibody binding assays, we propose to study recipients of HLA-identical sibling kidney transplants who have been transplanted at Barnes Hospital and normal HLA-identical sibling pairs for the presence of non-MHC antibodies and T cells response to non-MHC antigens. In the mouse the application of secondary CML to non-H-2 antigens has allowed in vitro testing of non-H-2 antigens and the recent production of non-H-2 antibodies may constitute a major breakthrough, allowing studies of non-H-2 antigens not previously possible. Through the use of the 19 congenic strains differing by segments of chromosome 2 which are housed in my animal facility and the expanded technology available, new information will be generated on genetic control, tissue distribution, immunogenicity and physical and chemical characteristics of the chromsome 2 membrane antigens. Of particular interest is the opportunity to study the fluctuating level of immunity directed aginst the H-13 antigen as a model of immune circuitry. The specific projects are as follows: 1. Studies of non-MHC antigens in man. 2. Further studies on a group of chromosome 2 congenic strains. 3. Studies on the immune response to H-3 and H-13 antigens. A. Production of antibodies to H-3 and H-13. B. Cellular immune response to H-3 and H-13 antigens. C. Studies of immune circuitry in the response to H-3 and H-13 antigens. D. The genetic control of immune response to H-3 and H-13. 4. Studies on the antigen expression of H-3 and H-13. 5. Studies on the physical and chemical characteristics of H-3 and H-13 antigens. 6. Functional studies on H-3 and H-13.